TDC/Crank sensor damage root cause

DS197

POTM Winner - June 2017
Paid Member
After my own experience with a crank sensor that failed and having done some research on the issue I thought this post would be of use to anyone who may have a similar issue.

As our cars get older and the clutch wears down, the crank sensor can get covered with dirt that may result in the car struggling to start or maintain a stable idle at times. Usually this can be remedied by taking out the sensor and cleaning it with brake cleaner which is a simple enough job for those with little mechanical experience.

However one issue which is somewhat common, especially on high mileage (60,000+ miles) cars on their original clutch is a piece of the clutch making contact with the crank sensor and damaging it or taking it out completely.

A part of the clutch breaks away from one end whilst the other is still attached. The reason why this happens in the first place could possibly be down to a quality control issue. This semi-loose piece of the clutch is now free to move within the bell housing and as the RPMs increase, so does the speed of the clutch which is how the offending loose piece of clutch makes contact with the crank sensor.

This explains why many of the reported failures happen on track days or during a spirited drive. Unfortunately by replacing the crank sensor, you won't be addressing the real issue which is a faulty clutch. The only fix is to replace the clutch and ideally as soon as possible to prevent the new crank sensor (if fitted) also becoming damaged and to prevent further damage to the bell housing as is quite common.

The car can be driven with a faulty clutch but in order to reduce the amount of damage caused by the clutch, the upper rev range should not be used. Instead the car should be driven at the lowest RPM possible for the type of road/driving you are doing. Lugging the engine won't be doing the car any favours either but that's a whole different story.

I've also attached a picture of my crank sensor below for reference. Hopefully this thread will be of use to the Clio owners on this site and any potential Clio owners in general.

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Great post - the previous owner to me actually replaced the crank sensor on my car. Later the clutch was dragging just slightly - it turns out the cover broke off slightly - which more and more people are discovering so it seems. It's worth getting it replaced as soon as you realise to help avoid damage to 3rd/4th.

I'll try and post some photos over the next couple of days from when mine happened.
 
Good & interesting bit of info.

I cant say I have had any issues but im now glad I changed my clutch this year with a new OE renault one.
 
I’ve just had my clutch replaced 9 months ago. Could a faulty/dirty crank sensor be causing my starting issues?